While agencies with adjacent or overlapping jurisdictions often have similar codes, it is not uncommon to find differences even within one county or city.
[1] The topic of standardized codes has been discussed in US law enforcement circles, but there is no consensus on the issue.
Arguments against plain language include its lack of brevity, variability, and lack of secrecy which is often tactically advantageous or a safety issue when officer communications can be overheard by the civilian public.
Additionally, "390" and variants are also radio codes only (CPC 647(f) is the legally enforced section "public intoxication").
Some agencies, such as the California Highway Patrol (CHP) use the current vehicle code numbers while municipal and county police agencies, especially the Los Angeles Police Department (LAPD) still use the 500 series.